The invention relates to a supporting disk for a supporting disk bearing for open-end spinning rotors, which supporting disk has a front side provided with at least one signal generator for non-contact revolution counting.
Supporting disks of this general type are described in German patent application 41 21 387. Two reflectors are embedded in suitable recesses in the surface of the front side, which are used for non-contact counting of revolutions of the open-end spinning rotors. In the case of heavy flue of the fiber material which is to be spun, a visual measurement, carried out with the aid of the reflectors, does not deliver a reliable signal.
In German patent application 25 07 199, corresponding to U.S. Pat. No. 4,150,530, the way the mentioned reflectors work is described. Accordingly, by means of non-contact counting of the revolutions of the spinning rotors, a piecing process is controlled by a travelling maintenance device. Here the reflectors are formed as colored markings, to which a photoelectrical impulse receiver is arranged at a short distance away from them, which receiver can be a component of a maintenance device, emitting a light beam which is variably reflected. The impulse receiver is connected to a plotting device. In the introductory part of the description, the fact that the triggering of the impulses can, when required, be activated by use of a capacitive or inductive proximity switch, is mentioned only briefly.
In German patent application 25 44 209, corresponding to U.S. Pat. No. 4,080,775, non-contact counting of the revolutions of spinning rotors is described with the aid of two equivalent ways, namely either by scanning the supporting disk or by scanning the shaft of the open-end spinning rotor. In the first case, the supporting disk has a marking which is scanned without contact by a measuring head during the run-up of the open-end spinning rotor. In the second case, the shaft of the open-end spinning rotor is provided with signal transmitting recesses around its circumference, which rotate past a measuring head.
In German patent application 24 22 943, a small metal false twist spindle arranged on supporting disks is described, which is provided with a cross hole and whose revolutions are scanned without contact by a sensor. The sensor comprises two coils whose magnetic fields are disturbed when the cross hole changes its position. This can be used to generate electrical signals in a plotting station.
In German patent application 39 26 664 it is disclosed that for the ascertainment of the current revolutions of an open-end spinning rotor, a sensor is advanced to the open-end spinning rotor. The open-end spinning rotor consists of ferromagnetic material and is magnetized at certain intervals. The magnetic field of the open-end spinning rotor changes with the revolutions of the open-end spinning rotor and generates various signals in this way.
In the case of practically constructed open-end spinning machines, supporting disks provided with reflectors have been used exclusively up to now for the purpose of non-contact revolution counting of open-end spinning rotors.
It is an object of the invention to carry out fail-safe revolution counting, even when the danger of flue on the supporting disks due to fiber material exists.
This and other objects are achieved according to the invention in that a signal generator is provided, which functions by means of magnetic field lines.
It is possible, while dispensing with an optical measurement, to receive reliable signals in relation to the current revolutions of the supporting disks and therefore indirectly those of the open-end spinning rotors, using the supporting disks according to the invention. This can take place in many ways.
In one version, a signal generator which generates magnetic field lines is provided, and which, for example generates an induction current in an impulse receiver; the said induction current is then evaluated at a plotting station.
In a second version a signal generator which alters magnetic field lines is provided, which for example alters the magnetic field of the coils of an impulse receiver and thereby generates plottable signals.
In the first version the signal generator is a permanent magnet, which can be fitted into a recess on the front side of the supporting disk.
In the second version, the signal generator can consist of a ferromagnetic material, for example in the form of a steel pin.
In both cases it is practical when the supporting disk consists of aluminum or synthetic material it should in any case be of a different material from that of the chosen material for the signal generator. It is advantageous when two signal generators are used which are disposed diametrically opposite to the axle of the supporting disk, so that problems of imbalance do not arise.
In the second version it is also possible for the signal generator to be a bore hole embedded in a base body of steel. An electrical signal can be alternatively received in this way.
For the sake of completeness it should be mentioned that two bore holes in the front side of the supporting disk can be used as signal genertors, whereby the inevitably arising air blast is registered and read as a signal.
In all the above it is advantageous when the front side has a flat surface. This is particularly favorable with regard to the energy consumption. Fitted-in steel or magnetic pins should be flush with the surface. Existing bore holes can, if required, be covered over with foil. Unnecessary air turbulence should be avoided at all times.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.